Fibrous dysplasia (FD) is a disease where normal bone is replaced with fibro-osseous tissue. In the polyostotic form, the anterior cranial base is frequently involved, including the sphenoid bones. The optic nerve passes through the sphenoid wing and is often found to be encased by FD on CT imaging. Controversy surrounds the management of fibrous dysplasia encased optic nerves, as optic neuropathy resulting in vision loss is the most frequently reported neurological complication, and there are strong proponents of prophylactic neurosurgical decompression. In collaboration with Dr. Michael Collins and Dr. Janice Lee of the Dental Institute, I prospectively examined 69 patients with fibrous dysplasia, of which 38 were included in this study. These patients all had detailed measurements made of their optic canals by CT and comprehensive neuro-ophthalmic exams. Of these patients, only 2 of the 38 had an abnormal neuro-ophthalmic exam suggesting optic neuropathy. The etiology in one case was felt to be due to stretch from an orbit grossly enlarged by excess growth hormone (concurrent acromegaly in a patient with McCune Albright syndrome). The other patient had normal acuity and was aymptomatic but did exhibit some mild color vision loss and optic nerve pallor in one eye. The conclusion is that although optic nerve encasement does occur, and constriction of the optic canal exists, the majority of the patients had normal eye exams. Therefore prophylactic optic nerve decompression is not recommended based on radiographic findings alone since they do not correlate with vision loss. This is the largest study to examine this question and provides ammunition to ophthalmologists trying to fend off cranio-facial surgeons from performing dangerous prophylactic surgery. The patients in this study will continue to be followed and some have been seen yearly for 3 years now with no change in their exams. Congenital nystagmus (CN) is an ocular-motor disorder of unknown etiology that presents at birth or early infancy and is clinically characterized by involuntary oscillations of the eyes. Dr. Richard Hertle and myself wished to determine the effectiveness of horizontal rectus tenotomy in changing the nystagmus of patients with CN and how their visual function may have changed. Using standard surgical techniques, in 10 patients with CN all 4 horizontal eye muscles were removed and reattached at the original insertion. Eye movement recordings and clinical examinations were performed before and at 1, 6, 24 and 52 weeks after surgery. In nine of the ten adult patients studied with CN, tenotomy resulted in significant improvements in a nystagmus measure and subjective visual functions.